We can remove an ordered broadcast with abortBroadcast(), is there a way to completely remove a sticky ordered broadcast?
removeStickyBroadcast is exactly what you need:
public abstract void removeStickyBroadcast (Intent intent)
Since: API Level 1
Remove the data previously sent with sendStickyBroadcast(Intent), so that it is as if the sticky broadcast had never happened.
You must hold the BROADCAST_STICKY permission in order to use this API. If you do not hold that permission, SecurityException will be thrown.
Parameters
intent The Intent that was previously broadcast.
http://developer.android.com/reference/android/content/Context.html#removeStickyBroadcast(android.content.Intent)
Related
Where can I find information which Intent/Broadcast can be sticky?
Example of a sticky broadcast sent via the operating system is ACTION_BATTERY_CHANGED. When I call registerReceiver() for that action with a null BroadcastReceiver — I get the Intent that was last Broadcast for that action.
Whenever I find the last value by:
//In Activity
val batteryIntent = registerReceiver(null, IntentFilter(Intent.ACTION_BATTERY_CHANGED)); //sticky
val level = batteryIntent?.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
val scale = batteryIntent?.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
This Intent: AudioManager.ACTION_HEADSET_PLUG works too, but some Intents don't work: LocationManager.MODE_CHANGED_ACTION, Intent.ACTION_POWER_CONNECTED BluetoothDevice.ACTION_ACL_CONNECTED, ... I know, some don't make sense, but result of these Intents are always null, even if there has been a change, why?
For ACTION_BATTERY_CHANGED there is information: "This is a sticky broadcast ..." in doc, but for ACTION_HEADSET_PLUG no.
Is exist any restriction or split to sticky / non-sticky or list which Intents work as sticky?
Why do some Intents work and others don't?
Thank you.
Where can I find information which Intent/Broadcast can be sticky?
Look at the source code for the Android version of interest, searching for sendStickyBroadcast().
Is exist any restriction or split to sticky / non-sticky or list which Intents work as sticky?
Sticky broadcasts are sent using sendStickyBroadcast(). Technically, it is not tied to a specific Intent.
In Android 5.0 onwards, HidService.java includes following function:
private void broadcastReport(BluetoothDevice device, byte[] report, int rpt_size) {
Intent intent = new Intent(BluetoothInputDevice.ACTION_REPORT);
intent.putExtra(BluetoothDevice.EXTRA_DEVICE, device);
intent.putExtra(BluetoothInputDevice.EXTRA_REPORT, report);
intent.putExtra(BluetoothInputDevice.EXTRA_REPORT_BUFFER_SIZE, rpt_size);
intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
sendBroadcast(intent, BLUETOOTH_PERM);
}
I am not able to find any documentation on this flag in the intent. How should I receive this broadcast intent in my app?
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Edited content deleted and formed into new question here
This constant is not documented in the Intent API docs because it is not intended for public use.
Here is a description from the android source code I found that describes it. (line 3018)
FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT
public static final int FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT
If set, when sending a broadcast before boot has completed only registered receivers will be called -- no BroadcastReceiver components will be launched. Sticky intent state will be recorded properly even if no receivers wind up being called. If FLAG_RECEIVER_REGISTERED_ONLY is specified in the broadcast intent, this flag is unnecessary.
This flag is only for use by system sevices as a convenience to avoid having to implement a more complex mechanism around detection of boot completion.
Emphasis mine.
In android there are 3 kinds of Intents,
Intent,
Sticky Intent,
Pending intent.
so What is sticky intent?
Intent - is a message passing mechanism between components of Android, except for Content Provider. You can use Intent to start any
component.
Sticky Intent - Sticks with Android, for future broadcast listeners. For example if BATTERY_LOW event occurs then that Intent
will stick with Android so that any future requests for
BATTERY_LOW, will return the Intent.
Pending Intent - If you want some one to perform any Intent operation at future point of time on behalf of you, then we will use
Pending Intent.
An intent that is used with sticky broadcast, is called as sticky intent.
This intent will stick with android system for future broadcast receiver requests.
OR
sendStickyBroadcast() performs a sendBroadcast(Intent) known as sticky, i.e. the Intent you are sending stays around after the broadcast is complete, so that others can quickly retrieve that data through the return value of registerReceiver(BroadcastReceiver, IntentFilter). In all other ways, this behaves the same as sendBroadcast(Intent). One example of a sticky broadcast sent via the operating system is ACTION_BATTERY_CHANGED. When you call registerReceiver() for that action -- even with a null BroadcastReceiver -- you get the Intent that was last broadcast for that action. Hence, you can use this to find the state of the battery without necessarily registering for all future state changes in the battery.
Pending Intent: Pending Intent is actually an object which wraps an Intent to do some future work by another app.
It lets us pass a future Intent to another application and allows that application to execute that Intent as if it had the same permissions as our application, whether or not our application is still around when the Intent is eventually invoked.
A PendingIntent is generally used in cases were an AlarmManager needs to be executed or for Notifications. A PendingIntent provides a mean for applications to work, even after their process exits.
PendingIntent uses the following methods to handle the different types of intents:
PendingIntent.getActivity() : Retrieve a PendingIntent to start an Activity
PendingIntent.getBroadcast() : Retrieve a PendingIntent to perform a Broadcast
PendingIntent.getService() : Retrieve a PendingIntent to start a Service
Example :
Intent intent = new Intent(this, SomeActivity.class);
// Creating a pending intent and wrapping our intent
PendingIntent pendingIntent = PendingIntent.getActivity(this, 1, intent, PendingIntent.FLAG_UPDATE_CURRENT);
try {
// Perform the operation associated with our pendingIntent
pendingIntent.send();
} catch (PendingIntent.CanceledException e) {
e.printStackTrace();
}
Intent: Intent is basically a message passing mechanism between different components of Android, except for Content Provider. You can use intent to start any component in Android.
Sticky Intent: These are the Intents which sticks with Android for future broadcast listener.
Sticky Intent is also a type of Intent which allows communication between a function and a service sendStickyBroadcast(), performs a sendBroadcast(Intent) known as sticky, the Intent you are sending stays around after the broadcast is complete, so that others can quickly retrieve that data through the return value of registerReceiver(BroadcastReceiver, IntentFilter). In all other ways, this behaves the same as sendBroadcast(Intent).
One example of a sticky broadcast sent via the operating system is ACTION_BATTERY_CHANGED. When you call registerReceiver() for that action — even with a null BroadcastReceiver — you get the Intent that was last Broadcast for that action. Hence, you can use this to find the state of the battery without necessarily registering for all future state changes in the battery.
Intent : Intent is an asynchronous message which is use to communicate between the components in android , except Content Provider.
for example you can start activity by
startActivity(Intent intent);
Sticky Intent : sticky intents are associated with the android system for the future broadcast events.
Pending Intent : Those intent which you want to trigger at some time in future when you application is not alive.
An intent that is used with sticky broadcast, is called as sticky intent. This intent will stick with android system for future broadcast receiver requests.
Sticky Intent allows a communication between function and a service sendStickyBroadcast() performs a sendBroadcast(Intent) know as sticky, the Intent you are sending stays around after the broadcast is complete so that others can quickly retrieve that data through the return value of registerReceiver(BroadcastReceiver, IntentFilter). In all other ways, this works the same as sendBroadcast(Intent).
I'm using this code:
Intent i = getApplicationContext().registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
and as far as I understand i should be null if ACTION_BATTERY_CHANGED didn't occur, but it is never null and always returns me the same data.
It worked fine when I used a broadcast receiver. Do I need to delete the Intent after receiving it?
As soon as you register sticky intents will always deliver you last broadcasted data. So that is the reason you are always recieving data
Sticky=property of adhering
result=which intent adhered with os called sticky intent
Normally you send broadcast a receiver using sendBroadcast(Intent) But When you are calling this method sendStickyBroadcast(Intent) it means that A broadcast Intent can be specified to be sticky in which case it will be retained by the system after it has been sent. But by default Intent.ACTION_BATTERY_CHANGED intent is sticky.
read the full post here http://iphoidtech.com/uncategorized/what-is-stcky-intent/
At the moment I am developing an application which catches the action NEW_OUTGOING_CALL with the help of a BroadcastReceiver. I am aborting the call by calling setResultData(null). After that I am showing the user a dialog which allows him to decide if he wants to use my application to rewrite its number. When the users decision has happened I am placing the new call depending on the decision. Now my broadcast receiver gets called up once again.
What is the correct way of getting to know that I have already processed the number? I got a working solution that uses a timestamp to guess if it could be already processed. Another solution would be to add a "+" at the end of the processed number.
These methods are working fine for my application being the only one catching the NEW_OUTGOING_CALL event. But what should I do when other applications (like Sipdroid or Google Voice) are also sitting there catching the NEW_OUTGOING_CALL broadcast aborting it and restarting it again? I don't see a possibility to get to know if we are still in the same "call flow" and if I already processed the number.
I would love to hear your ideas about this problem!
What API level are you working with? If it's >= 11, check out the new BroadcastReceiver.goAsync function that lets you extend the processing of the broadcast outside of the onReceive function of your receiver. This could bypass the need to loop altogether.
If, like me, you're stuck trying to do this before level 11, it is surprisingly tricky to do this elegantly. You may have done this as well, but I tried to include a "processed" flag as an extra in the ACTION_CALL intent that my code generated, hoping that it would somehow get included in the resulting ACTION_NEW_OUTGOING_CALL broadcast, but that sadly does not work.
The best solution I have been able to find is including a fragment in the URI for the ACTION_CALL intent that you generate. This fragment will be included for the resulting ACTION_NEW_OUTGOING_CALL broadcast, so your broadcast receiver can differentiate between the original call and the one that you generate, but it won't interfere with handlers that aren't looking for it.
Here's the basic code.
In your BroadcastReceiver for the ACTION_NEW_OUTGOING_CALL
public class YourBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// extract the fragment from the URI
String uriFragment = Uri.parse(
intent.getStringExtra("android.phone.extra.ORIGINAL_URI")).getFragment();
// if the fragment is missing or does not have your flag, it is new
if (uriFragment == null || !uriFragment.contains("your_flag")) {
// launch your activity, pass the phone number, etc.
// use getResultData to get the number in order to respect
// earlier broadcast receivers
...
// abort the broadcast
this.setResultData(null);
this.abortBroadcast();
}
// otherwise, your code is there, this call was triggered by you
else {
// unless you have a special need, you'll probably just let the broadcast
// go through here
// note that resultData ignores the fragment, so other receivers should
// be blissfully unaware of it
}
}
}
When the user first dials the number, the fragment will either be missing altogether or your flag won't be present, so you'll abort the broadcast and start your activity. In your activity, if you decide to place the call again, do something like the following:
startActivity(new Intent(Intent.ACTION_CALL,
Uri.parse("tel:" + modified_number + "#your_flag")));
The "your_flag" fragment will then be present in the subsequent NEW_OUTGOING_CALL broadcast and thus allow you to handle this case differently in your broadcast receiver.
The nice thing about this is the the fragment is completely ignored unless you look for it in the ORIGINAL_URI, so other broadcast receivers can continue to function. If you want to be really nice, you may want to look for an existing fragment and add your flag to it (perhaps with a comma separator).
I hope that helps. Good luck!
I don't see a possibility to get to
know if we are still in the same "call
flow" and if I already processed the
number.
Technically, you are not in the same "call flow" as placing a new call is asynchronous. You have to use hints (such as a timestamp) as you seem to be doing already.
If you are confident that other applications will not rewrite the number except to change the prefix or to add a suffix, you may want to add another "proximity check" hint to avoid false positives/negatives, but I'm afraid that's about all you can do.
The onReceive() method in Broadcast receiver receives an Intent as an argument.
Extract the Bundle from the Intent using Intent.getExtras().
This Bundle contains 3 key-value pairs as follows :
android.phone.extra.ALREADY_CALLED = null
android.intent.extra.PHONE_NUMBER = 98xxxxxx98
android.phone.extra.ORIGINAL_URI = tel:98xxxxxx98
98xxxxxx98 is the number dialled by the user.
When the onReceive() is called again, this number changes to 98xxxxxx98* or 0*
By checking for the asterisk(*) at the end of the dialled number, it can be inferred if the onReceive() method is called for the first time or the next subsequent times.
One of the answers would be to track the boolean extra in the intent. It is done in similar way by the Google Phone app. You can check this BroadcastReceiver here (look for alreadyCalled usage)
The other way would be just to pass that "rewritten" number from your broadcast to the next broadcast receiver down the road (can be any app, like Sipdroid, Google Voice, or custom VoIP app) without calling ACTION_CALL intent (this is why you get loop and you broadcast receiver called again) The following code is example of how I am handling call in my custom VoIP app. When I intercept NEW_OUTGOING_CALL in my broadcast receiver, I first check if there is internet connection. If phone is connected to internet I use custom defined intent action of my activity to place call through my VoIP app. If there is no internet connection, I just set original phone number to the broadcast receiver result data. This is used by the next broadcast receiver (probably default phone app, but doesn't have to be) in the flow to place a call.
public class BHTTalkerCallReceiver extends BroadcastReceiver {
private static final String TAG = "BHTTalkerCallReceiver";
#Override
public void onReceive(Context context, Intent intent) {
Log.d(TAG, "Broadcast successfull ... ");
// Extract phone number reformatted by previous receivers
String phoneNumber = getResultData();
if (phoneNumber == null) {
// No reformatted number, use the original
phoneNumber = intent.getStringExtra(Intent.EXTRA_PHONE_NUMBER);
}
if (isNetworkAvailable(context)) { // Make sure this app handles call only if there is internet connection
// My app will bring up the call, so cancel the broadcast
setResultData(null);
// Start my app to bring up the call
Intent voipCallIntent = new Intent(context, TalkerActivity.class);
voipCallIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
voipCallIntent.putExtra(TalkerActivity.OUT_CALL_NUMBER, phoneNumber);
voipCallIntent.setAction(TalkerActivity.BHT_TALKER_OUT_CALL);
context.startActivity(voipCallIntent);
} else { //otherwise make a regular call...
// Forward phone data to standard phone call
setResultData(phoneNumber);
}
}
private boolean isNetworkAvailable(final Context context) {
final ConnectivityManager connectivityManager = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE));
return connectivityManager.getActiveNetworkInfo() != null && connectivityManager.getActiveNetworkInfo().isConnected();
}
}